1. Field of the Invention
This invention relates to catheters for insertion into a cavity, duct, or vessel to permit injection or withdrawal of fluids or to establish patency of a passageway, and especially relates to a urinary catheter for insertion through a person's urethra and into a person's bladder for draining urine from the bladder and/or injecting irrigation fluid into the bladder.
2. Description of the Prior Art
The Foley catheter has found wide-spread use for decades as a urinary catheter. The Foley catheter comprises an elongated tubular catheter body having a distal end and a proximal end, and a drainage lumen extending through the catheter body from just short of the distal end to the proximal end. An opening or eyelet is provided in the catheter body just short of the distal end of the catheter body to permit urine to drain from a patient's bladder into the drainage lumen, as well as to permit irrigation fluid to flow from the drainage lumen into a person's bladder when it is desired to irrigate the patient's bladder.
The Foley catheter is provided with an inflatable retaining balloon near the distal end of the catheter body, located short of the opening to the drainage lumen, for securing the distal end of the catheter body in the patient's bladder. The retaining balloon is filled by injecting fluid with a syringe through a small filling channel. The fluid is retained by a valve which closes after removal of the syringe.
A problem with the Foley catheter is that pooling of urine and other fluids within a patient's bladder often occurs due to improper design. This urine pooling problem occurs because good drainage of urine from a patient's bladder is often difficult or impossible using a Foley catheter. Due to the structure of the Foley catheter, the opening to the drainage lumen is positioned above or away from the entrance to the patient's urethra when the distal end of the catheter body is retained in a patient's bladder since the opening to the drainage lumen is positioned between the retaining balloon and the distal end of the catheter body. Similarly, due to the structure of the Foley catheter, properly irrigating a patient's bladder using a Foley catheter is often difficult.
Another problem with the Foley catheter is that the tip or nipple portion of the Foley catheter sometimes irritates the patient's bladder.
Another problem with the Foley catheter is that severe injury may occur to a patient if the catheter is removed from the patient's bladder before the retaining balloon is deflated.
Another type of catheter is called the "Mallacote" catheter or mushroom catheter. This catheter has a drainage lumen extending through its elongated tubular body, and a "web-like" retaining structure near its distal end for securing the distal end of the catheter body in a patient's bladder. However, the catheter requires a stylet to be used to flatten the web-like retaining structure when inserting the distal end of the catheter body through the patient's urethra and into the patient's bladder. Further, "web-like" retaining structure is flexible and can easily collapse if the catheter is pulled on, resulting in the catheter not staying in place. This type of catheter also has a tip at its distal end which sometimes irritates the patient's bladder.